Development of an Unfractionated Pickering emulsion Stabilizer Using Black Turmeric (Curcuma aeruginosa) Pomace: An Analysis on the Physical Properties

Abstract

Jamu, an Indonesian traditional medicinal drink derived from rhizomes, could potentially raise environmental problems if the pomace byproduct is not improperly handled. A sustainable approach to solve this problem is by using the pomace into a Pickering emulsion. In this research, the capability of black turmeric (Curcuma aeruginosa) pomace to serve this purpose was analyzed by investigating the impact of the oil-powder ratio and milling process (knife milling and ball milling) towards the stability of a Pickering emulsion system. The physical stability analysis including backscattered value (BSV), coalescence index (Coal), and creaming index (CI) were performed. Additionally, texture and microscopy analysis were conducted on the sample produced using different milling methods. The result revealed that the reduction of oil (up to 30%) and increase of powder (up to 8%) caused a gradual increase in BSV (up to around 60%). Coal was enhanced up to 0% (i.e. no coalescence) when the powder and oil concentrations were set at 7% and 30%, respectively. CI was effectively reduced to 0% using the combination of 50% oil with 6% powder. Moreover, emulsion stabilized using a ball milled (BM) sample had a better stability than the knife milled (KM) as the BSV were significantly higher in BM (p<0.05) with significant reduction (p<0.05) in coalescence and creaming occurrence due to a firmer result as well as the smaller droplets in BM. To conclude, black turmeric was proven to be able to act as an emulsion stabilizer though Pickering mechanism.